Whipstock for wells



Sept. 26, 1933. J. s. ABERCROMBIE WHIPSTOCK FOR WELLS Filed May 1'7, 1928 011M WINVENTOR.

v ATTORNEYS.

Patented Sept. 26, 1933 UNITED STATES PATENT OFFICE 9 Claims.

My invention relates to whipstocks employed in sidetracking operations in wells.

When a drill bit has twisted off in a well or where other tools or pipe have fallen or broken 6 and become lost in the hole, it is sometimes de- 10 and thus enable the driller to go past the junk in the hole and continue the drilling of the well.

The usual whipstock is made up of a cylindrical bar of steel, the forward end of which is adapted to engage with the junk at the bottom of the well and the upper end is flattened on one side and tapered with a gradual taper to the extreme upper end. Sometimes this flattened side is also slightly concave so as to receive the drill or milling tool and deflect it laterally against the wall of the hole. The difliculty with the ordinary whipstock is that the drill may engage against the flattened edge of the deflecting face and rotate the whipstock in such manner as to destroy the effectiveness of the whipstock and a good sidetracking of the bit is impossible.

It is an object of my invention to provide a whipstock having the upper deflecting end made convex instead of flattened or concave as is the general rule.

It is desired to provide a whipstock having its upper end tapered and rounded so that the rotating bit may not engage with any edges or corners of the whipstock and cause its rotation.

Referring to the drawing, herewith, Fig. 1 illustrates a vertical section through the bottom end of a well illustrating my improved whipstock therein, the whipstock and the tools in the well being shown in elevation. Fig. 2 is a transverse section taken on the plane 22 of Fig. 1.

Fig. 3 is a similar section taken on the plane 3--3 of Fig. 1 and Fig. 4 is a transverse on the plane 4-4 of Fig. 1.

In the drawing I have illustrated the lower end of a well 1 having therein a broken lower end of a drill bit 2 and it is to be understood that the drill stem has been broken off leaving the drill and a piece of the drill stem lodged in the bottom of the hole where it cannot be removed. In such case the whipstock indicated at 3 is in serted into the bottom of the hole and anchored between the junk and the wall of the well so that 55 it will not readily rotate.

My whipstock is preferably made out of a section of heavy drill pipe. Such a section is slotted at the lower end and the sides bent to a point as shown at 4 and welded together to make a polygonal sharpened end, which may most' advantageously engage the tools and "the wall of the well and resist rotation.

Openings 5 are preferably formed at the forward end to allow the circulation of liquid when desired.

The upper end is made tapered by cutting a sector of the pipe out of the upper end, said out out portion being wider at the upper end and tapered downwardly so that when it is removed and the edges of the opening fitted together and welded, the welded side will taper upwardly to an apex at the upper end. The shape of the tool when thus constructed can be seen from Figs.

2, 3 and 4. The opening 6 through the pipe is elliptical and for purposes of handling such tool the upper end may be left open and formed into a socket as shown at 7.

The socket 7 is threaded to receive a. drill stem or setting tool and the device'is then lowered to the bottom of the well and jarred into position as shown in Fig. 1. The setting tool is then unscrewed and withdrawn, leaving the whipstock in place.

The side tracking tool is then introduced into the well. A rock bit or fishtail bit is frequently employed for this purpose and such a bit is shown at 8. The bit is connected by means of a drill collar 9 to the end of the drill stem 10 by means of which it may be rotated. As will be under-' stood from the drawing, the edge of the rotating drill will engage with the inclined surface 11 upon the whipstock. As the drill is rotated it will be deflected laterally by the inclined surface 11 against the wall of the well and will be gradually pushed into the wall of the well so as to cut a hole-parallel with the originalwell hole 1.

I have found that the forming of the deflecting surface 10. with the convex surface as here shown enables the use of a drill of this character 100 for side tracking without danger of the bit engaging the whipstock in such manner as to cause its rotation. A positive deflection of the side tracking bit is thus accomplished. There is no danger of the rotation and movement of the whipstock so as to cause a failure in the operation of side tracking. It is to be understood that the present whipstock is particularly effective when used in open hole where there is no casing and in soft formations so that the drillbit will be readily deflected. In event the twist oil. or other obstruction occurs in a hard formation it is usual to insert a length of pipe sufficient to support the whipstock in a soft formation.

The further advantages of the construction will be obvious to those skilled in the art.

What I claim as new is:

1. A whipstock for wells comprising a cylindrical body sharpened at its forward end and having the upper end convexly tapered approximately to a point.

2. A-whipstock for wells comprising a cylindrical body having its lower portion cylindrical, the upper end having convex sides tapered to an approximate apex.

3. A whipstock for wells comprising a body having its lower portion cylindrical, the upper end being convexly tapered to an approximate apex, and a socket adjacent said apex end to engage a setting tool.

4. A tubular whipstock having its upper portion conical and tapered to the upper end.

body portion deformed to define a tool deflecting area, said area having a convex face to be con-- tacted by the tool.

8. A whipstock of the character described including a body portion, and a convex tool deflecting area formed thereon.

9. A whipstock including a cylindrical portion, and a conical portion, the longitudinal axes of said portions meeting at an angle.

JAMES S. ABERCROMBIE. 

